The scientific validity of any behavioral, biological, or biobehavioral study lies with the conditions under which data have been collected, and the quality of analyses that allow data to be understood or interpreted. The Research Design and Analysis Core (RDAC) is charged with the critical task of applying optimal experimental design and analytical methods to realize the full informational potential of data collected as part of KIDDRC projects. RDAC was established in 1995 to meet increasing demands by KIDDRC principal Investigators (Pls) for consultafion in complex designs and access to advanced statisfical expertise. In 2002, RDAC expanded to include bioinformatics supportnecessitated by microarray services instituted in Core Dand the first bioinformatics services at KU were born. Since our last renewal, the core has confinued to expand its activities by providing new services in support of our research Themes. We now are poised to assume significant new responsibilities in analyzing data from cutting edge technologies and clinical trials.